Current intervertebral devices are designed using three major principles: the anatomical limitations of the surgical approach, optimization of bone graft volume to promote bony fusion, and optimization of the device contact with vertebral endplates to resist subsidence. Current devices are generally static in that they cannot change shape or volume. Thus, current devices are limited by anatomy and technique and consequently may not provide optimal bone graft volume or surface contact.
A need exists for an intervertebral device or implant that can change shape and/or volume. Such a device benefits from the ability to be advanced to an implantation site in a first configuration having a reduced transverse dimension and subsequently transitioned to a second configuration having a desired transverse dimension at the implantation site. Such a device benefits from a rigid structure that can be held in the second configuration by plastic deformation of the material and/or a mechanism for locking the device in the second configuration. Such a device further benefits from being quickly implantable by a simple tool that places and positions the implant at the implantation site and further delivers bone graft material to fill an interior volume of the implant.